Satellite land mobile communication systems

The emergence of satellite land mobile services over the last 10 to 15 years is described together with future trends. The difficulties of providing a commercially viable voice service are discussed and alternatives, such as inclined orbit systems and satellites with very large antennas, are suggested as ways in which the initial disadvantages might be overcome. Data services for satellite land mobile traffic and the possibilities of including radio determination of vehicle location as part of these data services are also considered. Future systems, which could have their architecture strongly influenced by the use of onboard processing, are discussed